Drive assembly for moving piston within container

ABSTRACT

A drive assembly includes a drive ribbon that can be retracted and extended. The retracted ribbon defines a spiral and the extended ribbon defines a helix. The drive ribbon is incrementally moveable between the retracted spiral configuration and extended helical configuration to move a piston within a container. A medical delivery device for advancing a piston in a medicament container to expel a medicament can include such drive assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/080,130, filed Aug. 27, 2018, which is the National Stage ofInternational Application No. PCT/US2017/022259, filed Mar. 14, 2017,which claims priority and the benefit of U.S. provisional patentapplication Ser. No. 62/310,961, filed on Mar. 21, 2016 entitled MEDICALDELIVERY DEVICE WITH AXIALLY EXPANDABLE DRIVE MEMBER, the disclosure ofwhich is hereby incorporated herein by reference.

BACKGROUND

The present invention relates to medical delivery devices such asinjection devices.

Conventional injection devices are often used to inject a medicamentinto a patient.

For example, injection pens that receive disposable cartridgescontaining insulin are often used by diabetes patients. Such pensgenerally include an elongate rod that acts on a piston within thecartridge. As the rod advances the piston, the medicament within thecartridge is dispensed through a needle and into the patient.

The rod must project outwardly from the cartridge to engage a drivingmechanism within the pen throughout the injection process including whenthe rod has reached the limit of forward advancement into the cartridge.The rod must also be accommodated within the pen when it is has beenfully retracted so that the rod may be inserted into a fresh cartridgethat is filled with medicament. As a result, conventional injection pensare generally elongate and thin with the length of the injection penbeing more than twice the length of the cartridge barrel in which themedicament is contained. Similarly, for non-pen-shaped refillableinjection devices, the length of the device is generally more than twicethe length of the cartridge barrel in which the medicament is contained.

When such injection devices are used to self-administer the medicamentat different times throughout the day, it is desirable for the injectiondevice to be readily carried by the user. For example, diabetes patientsoften self-administer insulin using injection devices and carry thedevices with them throughout the day. While conventional injection pensand similar devices are sufficiently small to be portable, the length ofsuch devices often makes transport of the devices awkward.

SUMMARY

In one embodiment, a drive assembly for a device for use with acontainer is disclosed. The container has a container body and aslidable piston therein. The drive assembly includes a drive ribbonmovable between an axially retracted configuration and an axiallyextended configuration to advance said piston axially within thecontainer body. The drive ribbon includes a proximal edge section and adistal edge section. During movement of the drive ribbon, a retractedportion of the drive ribbon defines a spiral about a drive axis, and anextended portion of the drive ribbon defines a helical column about saiddrive axis in which the proximal edge section of the drive ribbon is inengaged with the distal edge section that is adjacent to the proximaledge section. The extended portion defines a distal end of the driveribbon that is disposed within the container body to advance saidpiston.

In another embodiment, a medical delivery device is disclosed, includingan axially expandable drive assembly, and a container having a containerbody and a slidable piston therein. The axially expandable driveassembly includes a drive ribbon movable between an axially retractedconfiguration and an axially extended configuration to advance saidpiston axially within the container body. The drive ribbon includes aproximal edge section and a distal edge section. During movement of thedrive ribbon, a retracted portion of the drive ribbon defines a spiralabout a drive axis, and an extended portion of the drive ribbon definesa helical column about said drive axis in which the proximal edgesection of the drive ribbon is in engaged with the distal edge sectionthat is adjacent to the proximal edge section. The extended portiondefines a distal end of the drive ribbon that is disposed within thecontainer body to advance said piston.

In yet another embodiment, a medical delivery device is disclosed,including a mechanical drive, an axially expandable drive assembly, anda container having a container body and a slidable piston therein. Theaxially expandable drive assembly includes a drive ribbon movablebetween an axially retracted configuration and an axially extendedconfiguration to advance said piston axially within the container body.The drive ribbon includes a proximal edge section and a distal edgesection. During movement of the drive ribbon, a retracted portion of thedrive ribbon defines a spiral about a drive axis, and an extendedportion of the drive ribbon defines a helical column about said driveaxis in which the proximal edge section of the drive ribbon isinterlockable with the distal edge section that is adjacent to theproximal edge section. The extended portion defines a distal end of thedrive ribbon that is disposed within the container body and contactablewith said piston. The mechanical drive is operably coupled with thedrive ribbon to move the drive ribbon from the axially retractedconfiguration to the axially extended configuration.

It is noted that several different features of the delivery device aredisclosed herein and these features may be combined in various differentconfigurations. While several different combinations of such featuresare described herein, the person having ordinary skill in the art willrealize that further such combinations not explicitly described hereinare also possible and enabled by the present disclosure and are withinthe scope of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this invention, and the mannerof attaining them, will become more apparent and the invention itselfwill be better understood by reference to the following description ofan embodiment of the invention taken in conjunction with theaccompanying drawings, wherein:

FIG. 1A is a side view of a first embodiment of a delivery device.

FIG. 1B is an end view of the first embodiment.

FIG. 1C is another end view of the first embodiment.

FIG. 1D is side view of the first embodiment with the cap removed and aneedle assembly attached.

FIG. 1E is an end view of the embodiment of FIG. 1D.

FIG. 1F is a perspective view of the first embodiment.

FIG. 2A is a side view of a prior art delivery device.

FIG. 2B is an end view of the prior art device.

FIG. 2C is another end view of the prior art device.

FIG. 2D is side view of the prior art device with the cap removed and aneedle assembly attached.

FIG. 2E is an end view of the prior art device of FIG. 2D.

FIG. 2F is a perspective view of the prior art device.

FIG. 3A is a side view of a second embodiment of a delivery device.

FIG. 3B is an end view of the second embodiment.

FIG. 3C is another end view of the second embodiment.

FIG. 3D is side view of the second embodiment with the cap removed and aneedle assembly attached.

FIG. 3E is an end view of the embodiment of FIG. 3D.

FIG. 3F is a perspective view of the second embodiment.

FIG. 4 is a partial schematic perspective view of the drive assembly.

FIG. 5 is a partial perspective view of the drive ribbon.

FIG. 6 is another perspective view of the drive ribbon.

FIG. 7 is another partial perspective view of the drive ribbon.

FIG. 8 is a detail partial perspective view of the drive ribbon.

FIG. 9 is another detail partial perspective view of the drive ribbon.

FIG. 10 is another detail partial perspective view of the drive ribbon.

FIG. 11 is a schematic perspective view showing an extended portion ofthe drive ribbon.

FIG. 12 is a perspective view of a ribbon thrust member.

FIG. 13 is a schematic perspective view showing a ribbon bearingassembly around a drive ribbon.

FIG. 14 is a schematic perspective view showing a mechanical driveassembly for engaging the drive ribbon.

FIG. 15 is a schematic perspective view of an alternative mechanicaldrive assembly.

FIG. 16 is a schematic perspective view of a drive ribbon and a storagebobbin.

FIG. 17 is a schematic view of the first embodiment.

FIG. 18 is partial perspective view showing the drive assembly and amedicament container.

FIG. 19 is another partial perspective view showing the drive assemblyand a medicament container.

FIG. 20 is a partial perspective view of the drive assembly.

FIG. 21 is a side view of another embodiment.

FIG. 22 is a partial exploded view of the embodiment of FIG. 21 .

FIG. 23 is a cross sectional view taken along line 23-23 of FIG. 26 .

FIG. 24 is a top view of the drive ribbon of the embodiment of FIG. 21 .

FIG. 25 is a view of detail D25 in FIG. 24 .

FIG. 25A is an end view of the drive ribbon of FIG. 24 .

FIG. 26 is a side view of a portion of the embodiment of FIG. 21 withthe housing removed.

FIG. 27 is a cross sectional view taken along line 27-27 of FIG. 26 andalso showing the ribbon bearing member.

FIG. 28 is a side view of the embodiment of FIG. 21 with the housingremoved.

FIG. 29 is an end view of the embodiment of FIG. 21 with the housingremoved.

FIG. 30 is a side view of another embodiment with the housing removed.

FIG. 31 is an end view of the embodiment of FIG. 30 with the housingremoved.

FIG. 32 is a perspective view of the embodiment of FIG. 30 with thehousing removed.

FIG. 33 is an exploded view of the embodiment of FIG. 30 without thehousing.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the exemplification set outherein illustrates an embodiment of the invention, in one form, theembodiment disclosed below is not intended to be exhaustive or to beconstrued as limiting the scope of the invention to the precise formdisclosed.

DETAILED DESCRIPTION

A first embodiment of a compact medical delivery device 20 is shown inFIGS. 1A-1F while a second embodiment of a compact medical deliverydevice 20A is illustrated in FIGS. 3A-3F. One conventional prior artmedical delivery device 21 is shown in FIGS. 2A-2F. The device 21illustrated in FIGS. 2A-2F is a Kwikpen injector commercially availablefrom Eli Lilly and Company which has headquarters in Indianapolis, Ind.and has a length of approximately 145 mm. As can be seen in a comparisonof FIGS. 1A, 2A and 3A, the compact medical delivery devices 20, 20A areconsiderably shorter in length than the conventional device 21. Theconventional device 21 is, however, thinner than compact devices 20, 20Aas can be seen with reference to FIGS. 1B, 1C, 2B, 2C, 3B and 3C.

Medical delivery device 20 receives a medicament container 22. Asschematically depicted in FIG. 17 , medicament container 22 includes acontainer body 24 holding a medicament 25, for example, insulin, insideits cylindrical barrel. A piston 26 is disposed within body 24 andadvancement of piston 26 within container body 24 expels medicament 25through outlet 28. In the illustrated embodiment, outlet 28 is aninjection needle having one end that pierces a septum of the containerand an opposite end that can be inserted into a patient to inject themedicament 25.

Device 20 also includes a support structure 30 that is adapted tosupport medicament container 22. Support structure 30 also functions asa device housing in the illustrated embodiment and is also referred toherein as a housing. Housing 30 also supports a drive assembly 32 foradvancing piston 26 and is adapted to be held in a human hand. Device 20and device 20A are generally similar but do have different housings withhousing 30A of device 20A being slightly larger than housing 30.

Both housings 30, 30A include a removable cap 31, 31A which arereleasably securable to housings 30, 30A and cover outlet/needle 28 whenthe device is not being used. FIGS. 1D and 3D illustrate devices 20, 20Awith caps 30, 30A removed while FIGS. 1A and 3A show caps 31, 31Ainstalled on housings 30, 30A. As can be seen in FIGS. 1D and 3D, thecaps 30, 30A are used to cover a standard needle that also has aremovable, cylindrical inner needle shield 29.

As can be seen with reference to FIGS. 3A and 3D, removal of cap 31Aexposes nearly the entire longitudinal length of container body 24.Generally, container body 24 will be formed out of glass or othertransparent material. By exposing this length of container body 24, theuser can visually determine the quantity of medicament 25 remaining incartridge body 24. In contrast, housing 30 only exposes the end ofmedicament container 22 near outlet 28 and provides an open slot 42 inhousing 30 to allow the user to visually determine the quantity ofmedicament 25 remaining in container body 24. A transparent material canbe used to form a window instead of using an open slot 42 to allow forsuch visual inspection.

Housing 30 includes a control knob 44 for controlling the setting of adosage, a button 45 for initiating an injection and an electronicdisplay 46 located on the end of housing 30. For example, knob 44 can berotated to set the injection dosage and central button 45 depressed toinitiate the injection process. Housing 30A includes controls 44A and anelectronic display 46A on the side of housing 30A. Controls 44A are usedto set an injection dosage while control button 45A on the end ofhousing 30A is used to initiate the injection procedure. While theillustrated embodiments have actuators located on the end of the housingfor initiating an injection other locations on the housing for such afeature may also be employed. For example, the thicker body of thehousing relative to conventional pens may cause some people to grasp thedevice differently and an actuator which initiates the injectionprocedure may alternatively be deployed on the side of housing. The gripof the patient may also depend upon where on the patient's body theinjection will occur and it may also be desirable in some embodiments toinclude multiple actuators on the housing to facilitate various grippingscenarios.

Medicament container 22 has a storage volume of at least 3 mL and isshown in the form of a conventional medicament cartridge. Supportstructure 30 may define an axial length of no more than 110 mm, or evenan axial length of no more than 100 mm. The axial length of supportstructures 30, 30A are indicated by reference numbers 48, 48Arespectively in FIGS. 1A and 3A. As evident from FIGS. 1A and 3A, theaxial length of the support structure as referred to herein includes theremovable caps. In the illustrated embodiments, the capped axial lengths48, 48A are both 105 mm. In the illustrated embodiment, the axial length48, 48A of devices 20, 20A is less than twice the axial length 49 ofcontainer 22 (not including needle 28). A standard 3 mL medicamentcartridge used for insulin has an axial length of 64 mm and a plungertravel of approximately 43 mm.

It is the use of a drive assembly 32 having a drive ribbon 40 whichallows devices 20, 20A to have relatively short axial lengths 48, 48A.FIG. 17 provides a schematic overall view of device 20 showing howcontainer 22 is positioned in support structure 30 relative to driveassembly 32. Drive assembly 32 includes a mechanical drive 38 coupledwith drive ribbon 40. Drive ribbon 40 is incrementally moveable betweena retracted configuration and an extended configuration. With amedicament container 22 installed in device 20, the movement of driveribbon from a retracted configuration to an extended configurationextends drive ribbon 40 and causes the advancement of piston 26 and theconsequent discharge of medicament through outlet 28.

Selective rotation of drive ribbon 40 by mechanical drive 38 causeseither the retraction or extension of drive ribbon 40. In theillustrated embodiment, mechanical drive 38 includes a DC electric motor34 and a battery 36, e.g., a single AAA battery or rechargeable lithiumion cell, for powering motor 34. Alternative arrangement could employ anexternal electrical power source or an alternative form of torquesupply. For example, a torque spring or other arrangement could bemanually tensioned with the selective release of such tension providingthe torque necessary to drive the operation of drive assembly 32.

Mechanical drive 38 is selectively coupled with the drive ribbon torotate ribbon 40 about a drive axis 50 in either rotational direction.In a first rotational direction it causes drive ribbon 40 to extendaxially, in the opposite second rotational direction it causes theretraction of drive ribbon 40. Rotation of drive ribbon 40 shifts theribbon between spiral and helical configurations. When drive ribbon 40is fully extended, the majority, if not all, of drive ribbon 40 will bein a helical configuration. When drive ribbon 40 is fully retracted, themajority, if not all, of drive ribbon 40 will be in a spiralconfiguration. In most axial positions, an extended portion 52 of driveribbon 40 will define a helix while a retracted portion 54 of driveribbon 40 will define a spiral. Rotation of drive ribbon 40 causes theribbon to incrementally shift between the two configurations.

FIGS. 5-11 provide detailed views of drive ribbon 40. FIG. 6 illustratesribbon 40 in a configuration wherein ribbon 40 is partially extended. InFIG. 6 , retracted portion 54 defines a spiral while extended portion 52defines a helix. In retracted portion 54, the axial end surface ofdistal edge section 56 of ribbon 40 for each of the spiral wraps lie ina common plane 110, similarly, the axial end surface of proximal edgesection 58 of each of the spiral wraps also lie in a common plane 112.This spiral arrangement allows the retracted portion 54 of ribbon 40 tobe stored in a minimal axial space that is approximately equal to thewidth of ribbon 40. In the extended portion 52 of drive ribbon 40,proximal edge section 56 is directly bearingly engaged with an adjacentportion of the distal edge section 58.

It is noted that FIGS. 6 and 11 show helical extended portion 52 withengaged edges while FIGS. 5 and 7 show an exploded view of drive ribbon40. FIGS. 5 and 7 are provided for purposes of explaining and showingthe details of ribbon 40. In use, drive ribbon 40 would not assume theexploded configuration shown in FIGS. 5 and 7 .

One of the proximal 58 and distal 56 edge sections of ribbon 40 define aradially extending lip 60 to directly and bearing engage the other oneof the proximal 58 and distal 56 edge sections. As can be seen in FIG. 8, in the illustrated embodiment, it is distal edge section 56 thatincludes a radially extending lip 60 and that the illustrated lip 60extends radially inward. Lip 60 includes an axially facing surface 62that is generally perpendicular to axis 50 which engages opposingproximal edge 58 to allow for the transfer of axially compressiveforces. Ribbon 40 also provides for the transfer of torque forces. Oneof the proximal 58 and distal 56 edge sections of ribbon 40 defines aplurality of projections 64 with the other one of the proximal 58 anddistal 56 edge sections defining a plurality of cooperating recesses 66.The interfitting of projections 64 with recesses 66 allow for thetransfer of torque and help keep the proximal 58 and distal 56 edgesections interlocked as ribbon 40 is rotated. As can be seen in FIGS. 8and 9 , in the illustrated embodiment, it is distal edge section 56 thatdefines the plurality of recesses 66 and it is proximal edge section 58that defines the plurality of projections 64. It is noted that it is theengagement of sidewall surfaces 68 of recesses 66 with sidewall surfaces70 of projections 64 that allow for the transfer of torque. Sidewallsurfaces 68 and 70 both define planar surfaces that are orientedsubstantially radially relative to axis 50. This radial orientation ofthe engaged sidewall surfaces resists shear forces along the joint andthus torsion in the column formed by the extended ribbon 40. Variousother arrangements and configurations of the cooperating projections 64and recesses 66 can be used. For example, recesses 66 could formopenings that extend through the full thickness of ribbon 40. As aresult of the resistance to shear forces along joint formed by theengaged edges, the resulting column carries torsional loads preventingone end from rotating relative to the opposite end. It also resists thetwisting and uncoiling of the column formed by extended portion 52 ofribbon 40.

Distal 56 and proximal 58 edge sections also include radially extendingflanges 72, 74 respectively. Flange 72 on distal edge section 56 extendsradially inwardly while flange 74 on proximal edge section 58 extendsradially outwardly. When the distal and proximal edge sections 56, 58are engaged, radially outwardly extending flange 74 is seated in groove76 defined by lip 60 and flange 72. Engagement of flanges 72, 74provides resistance to axially acting tensile forces and prevents theengaged distal and proximal edge sections 56, 58 from axially separatingwhen subjected to axially acting tensile forces.

When deployed the ribbon 40 is formed into a helix to form aninterlocked rigid cylindrical column. Interlocking of the distal 56 andproximal 58 edge sections gives the column axial and torsional rigidityand strength as described above. The ribbon edge sections 56, 58mechanically engage one another in a detachable and re-attachablemanner. The deployment process, discussed below, is continuous, enablinga smooth and accurate injection process.

The column formed by extended portion 52 of ribbon 40 acts as acontinuous tubular structure and will primarily carry compressive axialloads which correspond to the force necessary to expel medicament fromcontainer 22. It will also carry some torsional loads generated by therotation of ribbon 40 as ribbon 40 is extended and retracted. Althoughno axial tensile loads are generally applied to ribbon 40, the use ofinterfitting flanges 72, 74 provides resistance to axial tensile loadsand thereby prevents the engaged edges of ribbon 40 from axialseparation during use and enhances the reliability of ribbon 40.

Drive ribbon 40 also defines a plurality of gear teeth 76 that areengageable with mechanical drive 38 whereby mechanical drive 38 canrotate drive ribbon 40 by transmitting a rotational force through theplurality of gear teeth 76. As can be seen in FIGS. 8 and 9 , gear teeth76 are disposed on the radially inward facing surface of ribbon 40.While gear teeth 76 are disposed on the inner face of ribbon 40, analternative arrangement may utilize gear teeth on the radially exteriorsurface of ribbon 40. FIG. 10 illustrates a set of gear teeth 78 on theexterior surface of ribbon 40 that are formed by a series of recesses.Either internal 76 or external 78 gear teeth can be used to rotateribbon 40. Still other variations are also possible, for example, gearteeth could be employed on the proximal edge of ribbon 40 or bothinternal and external gear teeth could be employed on the same ribbon.Engagement and rotation of ribbon 40 by mechanical drive 38 is discussedin greater detail below.

The illustrated embodiments of drive ribbon 40 utilize a flexiblepolymeric ribbon that has been machined to define the various featuresof the ribbon. Nylon, polypropylene and high density polyethylene areexamples of suitable polymeric materials that may be used to form ribbon40. While the illustrated embodiments are machined, alternativeembodiments could use a molding process to form a polymeric ribbon 40with all of its edge features. It is envisioned that molding the ribbonin a flat arrangement and then rolling the ribbon into a spiralconfiguration will be the most efficient manufacturing method of forminga ribbon 40.

Other materials may also be used to form ribbon 40. For example, thinmetal strip could be used to form ribbon 40. Photo etching, laseretching or other suitable micro machining methods could be used to formthe individual features of ribbon 40. Alternatively, a metal ribboncould be formed by diffusion bonding two half-thickness layers insteadof using a single metal strip.

Still other ribbon embodiments might take the form of an overmoldedmetal strip. The metal strip would be provided with the distal edgefeatures and the overmolded plastic portion of the ribbon would form theproximal edge features. This approach combines the desirable stiffness,elasticity and creep resistance of metal with the low friction andmanufacturing ease of forming small features in molded plastic. For allembodiments of ribbon 40, it is desirable for ribbon 40 to be flexibleso that ribbon 40 can be extended and retracted, and undergo concomitantelastic strains, without permanent deformation.

The distal end of ribbon 40 must exert axial forces on piston 26. Toenable such a transfer of force, a bearing member 80 is supported ondrive ribbon 40 proximate distal end 81 of drive ribbon 40 and isadapted to exert an axial force on piston 26. The column formed byribbon 40 will rotate as it extends, however, piston 26 of container 22does not rotate. A rotational bearing 82 is provided at the distal end81 of ribbon 40 to account for the relative rotational motion and allowrelative rotational movement between drive ribbon 40 and piston 26 aboutdrive axis 50. In the illustrated embodiment, rotational bearing 82 is ajewel bearing located on bearing member 80. In the illustratedembodiment, bearing member 80 is shown as an integral part of driveribbon 40, but the two can also be separate parts with a suitable jointtherebetween. As can be seen in FIG. 10 , a transfer member 84 acts onpiston 26 or other intermediate part and includes a projecting member 86that rotates within jewel bearing 82. Transfer member 84 pushes againstand advances piston 26 and does not rotate relative to piston 26 asribbon 40 is advanced. As ribbon 40 advances and ribbon 40 rotatesrelative to piston 26, projecting member 86 rotates within rotationalbearing 82. Since loads are predominantly axial and minimizingfrictional losses is desirable, the revolute joint at this location maybe a low-friction jewel bearing, however, other arrangements allowingfor relative rotation of ribbon 40 and piston 26 may also be used.

A thrust member 88 (FIG. 12 ) is operably disposed between supportstructure 30 and drive ribbon 40. Thrust member 88 is engaged with aportion of proximal edge 58 of ribbon 40 when drive ribbon 40 is atleast partially extended. More specifically, thrust member 88 engagesribbon 40 where ribbon 40 transitions between a spiral configuration anda helical configuration and also bears axial compressive forces actingon ribbon 40. In the illustrated embodiment, drive ribbon 40 is aone-piece unitary ribbon and all axial forces transferred betweenbearing member 80 and thrust member 88 when the drive ribbon 40 is atleast partially extended are transferred by the unitary one-piece ribbon40. The axial compressive load created by bearing on piston 26 istransmitted to the support structure 30 through bearing surface 91 onthe axial end of thrust member 88 opposite ramp 90. In this regard, itis noted that some of the axial compressive force acting on ribbon 40will act on the medicament in container 22 causing the ejection of themedicament through outlet 28.

It is also noted that the axial force exerted by the transfer member 84on piston 26 is at least partially transmitted to support structure 30through the medicament container 22 otherwise, container 22 would simplymove axially together with ribbon 40 as ribbon 40 was extended. Ifcontainer 22 is held within device 20, 20A by a friction fit withinsupport structure 30, this friction fit may be sufficient to holdcontainer 22 in place and absorb the axially compressive forces actingon container. Alternatively, a structural retainer could be used toretain container 22 in support structure 30. FIG. 18 schematicallydepicts how shoulder surface 128 of container 22 could be engaged bysliding a retainer with bearing surface 130 into engagement withshoulder 128. Compressive forces would be transferred from shoulder 128to surface 130 and, thus, to the retainer which is a part of supportstructure 30.

Thrust member 88 is rotationally fixed relative to housing 30 anddefines a helical ramp 90 that engages proximal edge 58 of ribbon 40.Compressive axial forces are transferred between ribbon 40 and thrustmember 88 at helical ramp 90. Helical ramp 90 also guides the transitionof ribbon 40 between its spiral and helical configurations.

When the drive ribbon is rotated in a first direction so that theproximal edge 58 engaged with ramp 90 is sliding upward and in a distaldirection, a transition portion 53 of ribbon 40 that is engaged withhelical ramp 90 is guided by ramp 90 into a helical arrangement and istransitioned from the retracted (spiral) configuration 54 to theextended (helical) configuration 52. Similarly, when ribbon 40 isrotated in a second, opposite, direction, transition portion 53 of theribbon 40 engaging the helical ramp 90 slides down ramp 90 andtransitions from the extended (helical) configuration 52 to theretracted (spiral) configuration 54.

Due to the limited area of contact between proximal edge section 58 andramp 90, the friction resisting sliding movement is relatively small. Tofurther limit frictional resistance to sliding along ramp 90, thrustmember 88 may be formed out of a lubricious polymeric material such asacetal. Proximal edge section 58 may form a continuous surface and avoidrecesses or interruptions in the portion of proximal edge section 58that engages ramp 90 to avoid the increased resistance and greater wearthat such irregular surfaces are likely to cause.

Alternative thrust support surfaces may also be used. For example,instead of using a sliding surface, small rollers could be arranged inhelical pattern along the outer perimeter of the thrust member. Due tothe small scale and small forces generally anticipated when using ribbon40 to inject a medicament, the greater manufacturing difficulties andexpense that such rollers would require will generally not be warranted.

An axially extending wall 92 is located on the radially inner edge ofhelical ramp 90 and extends in the distal direction. Wall 92 preventsproximal edge section 58 from being biased radially inward out ofengagement with ramp 90 by ribbon bearing member 100. Ribbon bearingmember 100 circumscribes thrust member 88 and exerts a radially inwardbearing force on drive ribbon 40 proximate helical ramp 90. Ribbonbearing member 100 includes a sleeve 102 that surrounds thrust member 88and a plurality of rollers 94 mounted within sleeve 102. Rollers 94 areengageable with drive ribbon 40 and exert a radially inward force andbias drive ribbon 40 onto helical ramp 90 as drive ribbon 40 is rotated.Rollers 94 include a cylindrical disk 96 which engages ribbon 40 andaxle stubs 98 extending from opposite sides of disk 96 which arerotatably mounted on the inner surface of sleeve 102.

Ribbon 40 is fed onto helical ramp 90 from the retracted portion 54 ofribbon 40 which is stored within bobbin 104 in a spiral configuration ascan be seen in FIG. 16 . The proximal end 106 of ribbon 40 is secured tobobbin 104 and as ribbon 40 is rotated, bobbin 104 rotates with ribbon40. In the illustrated embodiment, bobbin 104 is a cylindrical storagebobbin and is rotatably mounted on thrust member 88. In the illustratedembodiment, bobbin 104 includes an axially extending slot 108 in whichproximal end 106 of ribbon 40 is secured. Various other methods may alsobe used to secure proximal end 106 to bobbin 104. Both ribbon 40 andbobbin 106 rotate about axis 50.

As can be seen in FIG. 16 , for the retracted portion 54 of drive ribbon40 disposed within bobbin 104, the axial end surface of distal edgesection 56 of drive ribbon 40 lies in a first plane 110 orientedperpendicular to drive axis 50 and the axial end surface of proximaledge section 58 of drive ribbon 40 lies in a second plane 112 orientedperpendicular to drive axis 50. This spiral configuration allows ribbon40 to be stored in a minimal amount of space and is particularly usefulfor reducing the axial length of the storage space required to storeribbon 40. The distance between planes 110, 112 is equivalent to thewidth of ribbon 40, i.e., the shortest distance between the opposingaxial end surfaces defined by distal and proximal edge sections 56, 58of ribbon 40.

As can also be seen in FIG. 16 , the retracted portion 54 of ribbon 40fills storage bobbin 104 from the radially outermost location withinbobbin 104 inwardly with the innermost portions of the stored ribbon 40still defining a larger radius than the radius of helical ramp 90. Thisfacilitates the movement of ribbon 40 from the stored spiralconfiguration of retracted portion 54 to the extended helicalconfiguration of extended portion 52 by engagement of ribbon 40 withribbon bearing member 100.

It is desirable for ribbon 40 to naturally assume a coiled shape havinga radius larger than the inner diameter of bobbin 104 so that ribbon 40will expand to engage the inner surface of bobbin 104 when it is storedtherein. Some plastic materials tend to creep and take on their storeddimensions. The use of a metal ribbon or an overmolded metal ribbon willminimize the risk of having the ribbon fail to expand and fill theradially outermost portions of bobbin 104.

While the illustrated embodiment utilizes a cylindrical storage bobbin104 for ribbon 40, alternative embodiments are also possible. Forexample, a plurality of abutments within housing 30 may be sufficientfor some embodiments, or, if ribbon 40 has the appropriate physicalproperties, it might naturally assume a spiral configuration whendisengaged from an adjacent turn of the ribbon and thereby avoiding theuse of a storage bobbin.

The size of storage bobbin 104 is chosen so that it will be adequatewhen ribbon 40 is fully retracted. When fully retracted, ribbon 40 has aminimum radius that is larger than the radius of ramp 90 whichcorresponds to the radius of the helical extended portion 52 of ribbon40. When ribbon 40 is rotated in a direction that feeds stored ribbon 40from storage bobbin 104 onto helical ramp 90, each additional coil ofthe ribbon transitions from the inside of the storage spiral onto thecolumn formed by extended portion 52. The transition portion 53 ofribbon 40 gets radially smaller as it moves from its storedconfiguration in bobbin 104 onto ramp 90 and it becomes tangent to thehelical column formed by extended portion 52 at the point where theribbon 40 joins the helical column of extended portion 52. As the ribbonis moved radially inward along this helical path, the features along thedistal edge section 56 of the transition portion 53 of ribbon 40 engagethe features of the proximal edge section 58 of the lowermost turn ofthe extended portion 52 of ribbon 40.

The position where the radial lay-in and ribbon edge engagement occursremains fixed within the device and fixed relative to thrust member 88.Distally from this point of engagement the ribbon is a helical columnforming the extended portion 52; proximally from this point ofengagement the ribbon relaxes through the transition helical spiral(transition portion 53), into the spiral arrangement (retracted portion54) contained within storage bobbin 104.

All of the coils of ribbon 40 distal of the engagement location, i.e.,the extended portion 52 of ribbon 40, are kept engaged with each otherby the ribbon coil proximally below them. At the point of engagement,the proximal edge of the ribbon coil being engaged is still un-engagedand is biased radially inward by ribbon bearing member 100 so that theribbon coil being engaged does not expand radially outward and fail toengage. At the same time, ribbon 40 must be maintained in a positionencircling axis 50. These tasks are accomplished by external bearing 100which surrounds roughly one full helical coil of ribbon 40. Relative tothis fixed bearing 100, ribbon 40 both rotates and translates as ribbon40 advances (or retracts) along its helical path.

As discussed above, the illustrated embodiment utilizes a ribbon bearingmember 100 that includes a plurality of rollers 94. In this arrangement,each of the rollers 94 is tangent to the cylinder defined by ribbon 40and tilted at the helix angle. Rollers 94 roll rather than slide alongthe cylinder defined by ribbon 40. The position of the rollers 94establish and then maintain the engagement of the ribbon edge sections56, 58 while keeping the overall helical structure of the engaged ribbonedges supported both radially and axially. While the disclosed rollers94 are effective, alternative arrangements that are simpler and whichcan be more cost-effectively manufactured may be suitable for someapplications. For example, small ball bearings disposed in a groovesimilar to a conventional ball bearing or that found in a ball screw maybe suitable for some applications. A simple bushing formed out of alubricious polymeric material may also be adequate for someapplications.

FIG. 4 provides a partially transparent view of drive assembly 32 andviews of alternate drive assemblies are provided in FIGS. 14 and 15 . Inthe illustrated embodiments, drive assembly 32 includes a batterypowered electrical motor 34 and a mechanical drive 38. Mechanical drive38 includes motor shaft 114 which is driven by motor 34 and includes agearing arrangement 116 for transferring torque generated by motor 34.The transfer of torque from motor 34 to ribbon 40 allows ribbon 40 toperform mechanical work, i.e., forcibly rotate and advance ribbon 40 tothereby advance piston 26, or, when rotated in the opposite direction,retract ribbon 40 and wind it into a spiral in bobbin 104.

Small electrical motor 34 provides the power to operate the extensionand retraction of ribbon 40. Typically, motors of this size utilize amechanical gear reduction. Motor shaft angle sensing can be used tocontrol advancement of ribbon 40 and thus the dose delivered.

FIGS. 14 and 15 illustrate two different arrangements by which torquemay be transferred from motor 34 to ribbon 40. Various other torquetransfer arrangements and modifications to the illustrated arrangementsmay also be employed with drive ribbon 40.

In the embodiment of FIG. 14 , ribbon 40 includes gear teeth 76 on theinterior surface of ribbon 40. A gear member 124 having gear teeth 126that meshes with gear teeth 76 is used to rotate ribbon 40. Gear member124 includes a shaft (not shown) extending through opening 93 in thrustmember 88. The shaft includes another gear arrangement that meshes witha transfer gear member which is also engaged with gearing arrangement116 on motor shaft 114 whereby torque from motor 34 is transferred toribbon 40.

In the internal gear drive arrangement depicted in FIG. 14 , teeth 76 onthe inner wall of ribbon 40 engage a gear inside the helical columnformed by extended portion 52. As gear 124 rotates it causes ribbon 40to rotate and either extend or retract. In the illustrated embodiment,the rotational axis of gear 124 is parallel to axis 50 and slightlyoffset. This offset arrangement together with gear 124 having an outsidediameter less than the inner diameter of ribbon 40 at the location ofgear 124 allows gear 124 to engage ribbon 40 at one location onlyinstead of along the entire perimeter of gear 124. Gear teeth pitchesare selected to establish conventional meshed engagement. With astraight-toothed gear, the internal teeth 76 on ribbon 40 are tilted bythe helix angle (relative to the ribbon edge) to ensure correct meshing.Since ribbon 40 is extending (or retracting) as it rotates, the gearteeth slide axially along one another as ribbon 40 is rotated.

Drive gear 124 can also have helical teeth if the helical teeth aretilted to match the helix angle of extended portion 52. In such anapplication, ribbon teeth 76 can be perpendicular to the ribbon edge.Other relative angles between gear teeth 76 and ribbon edges 56, 58 arealso possible. Various other arrangements are also possible, forexample, alternative axis orientations are possible (for example, thegear could be arranged to be tangent to the helix).

The use of an internally positioned gear can be effective. For someapplications, however, it does pose drawbacks. For example, it willgenerally require that some mechanical elements such as a gear train torotate internal gear 124 be disposed at the proximal axial end of thrustmember 88. This can add additional axial length to the overall device.This arrangement also requires that a sufficiently radially rigidmechanical structure hold the external ribbon bearing member 100 inplace.

FIG. 15 illustrates an embodiment wherein ribbon 40 includes a gearingarrangement 78 on the exterior surface of ribbon 40. In this embodiment,two transfer gear members 118 transfer torque from motor shaft 114 toribbon 40. More specifically, transfer gear members 118 each include afirst gearing arrangement 120 that engages with gear arrangement 116 onshaft 114 and a worm gear 122 engaged with ribbon 40.

The external drive system shown in FIG. 15 uses a worm gear 122 enmeshedwith external-facing slots 78 on ribbon 40. The worm 122 may be chosento have a helix angle that matches the helix angle of extended portion52 of ribbon 40 to thereby allow the slots 78 cut into ribbon 40 to bearranged perpendicular to the ribbon edge. Although two worm gears 122are shown in FIG. 15 , a single worm gear 122 could alternatively beused. As the worm(s) rotate they advance or retract the ribbon.

The use of an external worm drive such as transfer gear members 118places the transfer gear member 118 on the side of ribbon 40 andtherefore adds no axial length to the device. Additionally, transfergear members 118 can reduce the number of rollers 94 because transfergear members 118 provide radial support to ribbon 40.

The illustrated container 22 is a replaceable cartridge. To facilitatethe convenient replacement of container 22 upon its depletion, acartridge retainer may be used. Such retainers are well known in the artand typically utilize a threaded joint or bayonet joint, however, othersuitable mechanical retention devices may also be used.

Another consideration regarding the replacement of container 22 isavoidance of user contact with extension portion 52 of ribbon 40. Whilecontact with extension portion 52 will not necessarily cause damage,rough handling of ribbon 40 has the potential to impair the operabilityof ribbon 40, e.g., disengaging edge sections 56, 58 of extended portion52. Various approaches can be used to inhibit or prevent such contact.For example, if the full length of extended portion 52 would be exposedupon removal of container 22, a mechanical interlock can be provided sothat ribbon 40 is retracted prior to removal of container 22. If onlythe distal end of container 22 is exposed and extended portion 52 isshielded from contact by housing 30, an electrical interlock can commandretraction of ribbon 40 when removal of container 22 is detected.

It is also noted that while the illustrated embodiments discussed hereinutilize replaceable containers 22 to allow for the re-use of devices 20and 20A-20C alternative embodiments could take the form of prefilleddisposable devices or use a medicament container that is re-filledinstead of discarded and replaced.

Another embodiment, device 20B, is shown in FIGS. 21-29 . Device 20B isgenerally similar to devices 20, 20A but has several modifications. Theoverall length of device 20B as shown in FIG. 21 is less than 110 mm.Device 20B dispenses medicament from a container 22 having a needle 28.A removable cap 31B covers needle 28 when device 20B is not in use andhas sufficient space to allow for the use of an inner needle shield 29.Support structure 30B provides a housing for drive assembly 32B. Acartridge sleeve 140 receives container 22 and has an opening 142through which needle 28 can be extended. Cartridge sleeve 140 is bestseen in FIG. 33 and includes a threaded portion 144 adjacent opening142. A securement cap 146 engages threaded portion 144 and is used tosecure needle 28 to cartridge sleeve 140. A set of rear threads 148secures cartridge sleeve 140 to the device. In the illustratedembodiments, rear threads 148 engage corresponding threads on anextension of the ribbon bearing member. The illustrated cartridge sleeve140 also includes an axially extending opening 150 that functions as awindow allowing a user to view the container 22 to see the quantity ofmedicament remaining therein without having to remove container 22.Cartridge sleeve 140 also provides a bearing surface which functions thesame as surface 130 and may be formed by an internal shoulder contactingthe narrowing portion of container 22. Various other means for securingcontainer 22 within the device may alternatively be used.

FIG. 22 illustrates the main components of drive assembly 32B. Driveassembly 32B includes a DC motor 34B having an output shaft 114B onwhich a first gear 116B is secured. Gear member 116B engages gearmembers 120B located on two transfer gears 118B. Gear members 116B, 120Bare cross axis involute helical gears. Worm gears 122B on transfer gears118B engage gear teeth 78B on the exterior of drive ribbon 40B torotatably drive ribbon 40B.

The worm gear pitch, gear ratio and pitch of gear slots 78B in ribbon40B are all selected to work together. In this regard, it is noted thatthe selection of an integer number of ribbon teeth per half turn of theextended ribbon is a significant factor in determining appropriatevalues for these pitches and gear ratios.

Drive ribbon 40B differs from the drive ribbon of devices 20, 20A. Driveribbon 40B includes a recessed area 152 along the proximal edge section58B of ribbon 40B that receives an adjacent portion of the distal edgesection 56B of ribbon 40B when ribbon 40B is extended and forms a helix.Recessed portion 152 does not, however, receive the full thickness ofdistal edge section 56B and a portion of both the distal and proximaledge sections project radially in opposite directions as a result.

A plurality of pegs 154 are located in recess 152 and engage acorresponding plurality of holes 156. In the illustrated embodiment,pegs 154 are located on the proximal edge section 58B with holes 156being located on the distal edge section 56B. These positions, however,could be reversed. As drive ribbon 40B is extended and formed into ahelix, the engagement of proximal edge section 58B with an adjacentportion of distal edge section 56B includes the engagement of pegs 154with holes 156. In the illustrated embodiment, pegs 154 have a chamferedsurface 155 that facilitates the entry and removal of pegs 154 fromholes 156.

The engagement of pegs 154 with holes 156 secures the adjacent portionsof drive ribbon 40B together axially. The engagement of pegs 154 andholes 156 also provides for the transfer of torque between adjacentportions of the extended ribbon and maintains the stability of thecolumn formed by the extended ribbon.

In the illustrated embodiment, drive ribbon 40B has a first majorsurface 158 and a second major surface 160 on the opposite side of driveribbon 40B. A plurality of gear teeth 78B are formed in first majorsurface 158. Gear teeth 78B are engaged by gear members 122B wherebydrive assembly 32B can rotate drive ribbon 40B by transmitting arotational force to drive ribbon 40B.

The configuration of drive ribbon 40B may take on a variety of differentforms. In the illustrated embodiment, the plurality of pegs 154, recess152, plurality of holes 156 and gear teeth 78B are all expressed on thefirst major surface 158. In this regard, it is noted that it is theopening of holes 156 on the second major surface 160 that receives pegs154. While it is not necessary for the proper functioning of holes 156for holes 156 to extend all the way to the first major surface 158, byextending holes 156 to the first major surface the manufacture of ribbon40B is facilitated. More specifically, it allows for the manufacture ofa flat ribbon having two flat planar surfaces and a subsequent machiningor milling operation that forms the plurality of pegs 154, recess 152,plurality of holes 156 and gear teeth 78B to be performed from the sideof the first major surface 158 and without requiring any such operationto be performed on the second major surface 160 forming the oppositeside of ribbon 40B. This reduces the handling of ribbon 40B duringmanufacture and thereby improves efficiency and reduces cost. Ribbon 40Bmay be formed out of ABS (acrylonitrile butadiene styrene) or othersuitable material. For example, while ABS is a relatively flexiblematerial, other relatively stiffer material such as polycarbonate andmetal ribbons may alternatively be used. When employing a relativelystiff material, it may be advantageous to use a plurality ofperforations along the length of the ribbon to enhance the flexibilityof the ribbon.

Prior to machining these features in ribbon 40B, it is a flat ribbonhaving two planar surfaces which are parallel to each other and withoutany features formed in the planar surface. As a result, after formingpegs 154, recess 152, holes 156 and gear teeth slots 78B, the outermostportions of the first and second major surfaces 158, 160 define planes159, 161 which are parallel with each other and the distance 162 betweenthese two planes 159, 161 defined by the first and second major surfacesdefines the greatest thickness of drive ribbon 40B.

As mentioned above, the proximal edge section 58B of drive ribbon 40Bincludes a recess 152 that extends for all or substantially all of thelength of drive ribbon 40B and a plurality of pegs 154 located withinrecess 152. Proximal edge section 58B defines a proximal edge surface164 having a first axially facing lengthwise portion 166 and a secondaxially facing lengthwise portion 168. Distal edge section 56B includesa plurality of holes 156 and defines a distal edge surface 170 having athird axially facing lengthwise portion 172 and a fourth axially facinglengthwise portion 174. First and second axially facing surface portions166, 168 face in an axial direction that is opposite than the axialdirection faced by third and fourth axially facing surface portions 172,174.

FIG. 24 shows ribbon 40B in an unrolled condition and detail D25 isshown in FIG. 25 . Another view of ribbon 40B is shown in FIG. 25A. Ascan be understood with reference to FIGS. 24, 25 and 25A, proximal edgesurface 164 and distal edge surface 170 extend between first and secondmajor surfaces 158, 160 and, when ribbon 40B forms a helix, are axiallyfacing in opposite directions. First surface portion 166 extendslengthwise relative to ribbon 40B and is proximate second major surface160 while second surface portion 168 extends lengthwise relative toribbon 40B and is proximate first major surface 158.

In the illustrated embodiment, first portion 166 and second portion 168are axially separated by recess 152. Third surface portion 172 extendslengthwise relative to ribbon 40B and is proximate second major surface160 while fourth surface portion 174 extends lengthwise relative toribbon 40B and is proximate first major surface 158. In the illustratedembodiment, third and fourth surface portions 172, 174 are coplanar. Itis further noted that in the illustrated ribbon 40B, both the first andsecond major surfaces 158, 160 are parallel with the plane defined bydrive ribbon 40B and the axially facing portions 166, 168, 172 and 174of the proximal and distal edge surfaces 164, 170 are orientedperpendicular to the first and second major surfaces 172, 174.

As best understood with reference to FIGS. 26 and 27 , in the extendedportion of drive ribbon 40B that forms a helix, proximal edge section58B is engaged with an adjacent portion of distal edge section 56B withthe second axially facing lengthwise portion 168 of proximal edgesurface 164 being engaged with the third axially facing lengthwiseportion 172 of distal edge surface 170. The first axially facinglengthwise portion 166 of proximal edge surface 164 and the fourthaxially facing lengthwise portion 174 of distal edge surface 170 extendradially outwardly in opposite directions. In the illustratedembodiment, the first axially facing lengthwise portion 166 extendsradially inwardly while the fourth axially facing lengthwise portion 174projects radially outwardly.

Thrust member 88B includes a helical thread 176 which is engaged withfirst axially facing lengthwise portion 166 of proximal edge surface164. Helical thread 176 can engage surface 166 of drive ribbon 40B inthe transition portion of drive ribbon 40B disposed between theretracted portion 54B defining a spiral and the extended portion 52Bdefining a helix of drive ribbon 40B. Because surface 166 projectsradially and is still exposed in the extended portion 52B of driveribbon 40B, helical thread 176 may also engage surface 166 in thehelical extended portion 52B of drive ribbon 40B. Moreover, thisarrangement also allows the helical thread 176 to engage surface 166 formore than 360 degrees about drive axis 50B. In the illustratedembodiment, helical thread 176 extends for greater than 360 degreesabout axis 50B.

The ability of helical thread 176 to engage surface 166 after theengagement of the proximal edge section 58B with distal edge section 56Ballows thread 176 to bear axial loads in the extended helical portion ofthe drive ribbon and thereby allow pegs 154 to mesh with holes 156 at alocation where no axial load is being carried by drive ribbon 40B.

A ribbon bearing member 100B circumscribes the drive ribbon and definesa second helical thread 178 engageable with the fourth lengthwiseportion 174 of distal edge surface 170. Thread 178 can engage surfaceportion 174 in the transition portion of drive ribbon 40B. However,because surface 174 projects radially and is still exposed in theextended portion 52B of drive ribbon 40B, helical thread 178 may alsoengage surface 174 in the helical extended portion 52B of drive ribbon40B. This arrangement also allows helical thread 178 to engage surface174 for more than 360 degrees about drive axis 50B. In the illustratedembodiment helical thread 178 extends for more than 360 degrees aboutdrive axis 50B and circumscribes drive ribbon 40B proximate thrustmember 88B. Ribbon bearing member 100B also supports gear members 118Band may be machined out of polyoxymethylene (POM), also known as acetal,polyacetal and polyformaldehyde or and sold under various tradenamessuch as Delrin, or formed using other suitable materials and methods.

By providing helical threads 176 and 178 which extend for more than 360degrees about drive axis 50B and positioning the threads proximate eachother, a short section of drive ribbon 40B is simultaneously constrainedby both threads 176 and 178 thereby firmly controlling the axialposition of the drive ribbon to facilitate the engagement of driveribbon 40B with itself. The use of a helical thread 176 on thrust member88B that extends for more than 360 degrees about drive axis 50B alsoincreases the surface area over which compressive axial forces can betransferred between drive ribbon 40B and thrust member 88B.

Both thrust member 88B and ribbon bearing member 100B remain stationaryrelative to each other and support structure 30B while drive ribbon 40Brotates about drive axis 50B relative to these parts when drive ribbon40B is being extended and retracted. Helical thread 176 on thrust member88B bears against ribbon 40B to thereby bear axial compressive forcesacting on the extended portion of drive ribbon 40B such as thosegenerated when drive ribbon 40B axially pushes a piston 26 in acontainer 22. Helical thread 178 is engageable with portion 174 ofdistal edge surface 170 and thereby resists tensile forces acting on thedrive ribbon 40B which would act to axially pull drive ribbon 40B awayfrom thrust member 88B. Helical threads 176, 178 also axially align thedrive ribbon with itself as the proximal edge section is engaged with anadjacent portion of the distal edge section as drive ribbon 40B isextended.

With regard to axially compressive forces, it is noted that theillustrated drive ribbon 40B is a unitary one-piece ribbon and all axialforces transferred between bearing member 80B and thrust member 88B whenthe drive ribbon is at least partially extended are transferred by theunitary one-piece drive ribbon 40B. Bearing member 80B includes twosecurement pegs 180 that are disposed in openings 182 in ribbon 40B. Atransfer member 84B is rotatably mounted on bearing member 80B andengages piston 26 when using device 20B.

Bearing member 80B transfers axial forces to drive ribbon 40B throughthe engagement of pegs 180 with openings 182 and through an overlappinglip that engages distal end surface 171 of the distal end of driveribbon 40B. The engagement of pegs 180 with openings 182 prevents therotation of bearing member 80B relative to drive ribbon 40B. As driveribbon 40B is extended, bearing member 80B will exert an axial force onpiston 26 to thereby cause the discharge of medicament from container22. In this regard, it is noted that bearing member 80B exerts thisaxial force on piston 26 through transfer member 84B which can rotaterelative to bearing member 80B. Thus, during discharge of a medicament,transfer member 84B will bear on piston 26 and will not rotate relativeto piston 26 but will rotate relative to bearing member 80B.

Axial compressive forces are transferred through ribbon 40B from bearingmember 80B to thrust member 88B through the engagement of the secondlengthwise portion of the proximal edge surface 168 with the thirdlengthwise portion of distal edge surface 172. Although the engagementof pegs 154 with holes 156 does not transfer compressive forces in theillustrated embodiment, alternative embodiments could utilize pegs andholes for this purpose. The engagement of the pegs 154 with holes 156 inthe illustrated embodiment does, however, resist axially directedtensile forces acting on ribbon 40B and thereby resists the separationof extended ribbon.

A bobbin 104B is rotatable relative to thrust member 88B and theretracted portion 54B of drive ribbon 40B is stored in bobbin 40B.Bobbin 40B rotates along with drive ribbon 40B due to frictionalengagement of drive ribbon 40B with bobbin 104B. In the illustratedembodiment, ribbon 40B is not attached to bobbin 104B. By not attachingribbon 40B to bobbin 104B, the short length of ribbon that would benecessary to extend to and be secured with the bobbin when the driveribbon is fully extended can be omitted. Various methods can be used toprevent the unsecured end of drive ribbon 40B from being overextendedand having drive ribbon 40B escape from the drive mechanism. Forexample, the gear slots 78B can be terminated on the drive ribbon 40B ata location that will limit the extension of ribbon 40B. A stop in theform of a hook or other catch type member could alternatively oradditionally be secured at the end of the drive ribbon that wouldprevent it from being moved through the gap between thrust member 88Band ribbon bearing member 100B. Alternatively, a controller whichgoverns operation of the motor in a manner that limits the extension ofdrive ribbon 40B and prevents escape of the ribbon can be employed.

The use of a rotating bobbin 104B helps prevent friction lock of theretracted portion of the drive ribbon during extension and retraction ofthe drive ribbon. Alternative methods of preventing such friction lock,such as the use of a lubricous material to form the drive ribbon mayalternatively be used and the rotating bobbin omitted.

In the illustrated version of drive ribbon 40B, a portion of theproximal edge surface projects radially inward while a portion of thedistal edge surface projects radially outward. It is noted that otherarrangements may also be used. For example, a portion of the proximaledge surface could project radially outward and a portion of the distaledge surface could project radially inward. In such an alternativeembodiment, the helical thread engaging the proximal edge surface andbearing axially compressive forces would be positioned radially outwardof the drive ribbon and the thread member engaging a portion of thedistal edge surface and positioned to resist axial tensile forces wouldbe positioned radially inward of the drive ribbon.

The offset arrangement of the edge surfaces causes one of the edgesurfaces to have a longer length per unit length of drive ribbon. In theillustrated embodiment, it is the distal edge that has a relativelylonger length. When drive ribbon 40B is unrolled and positioned in aplane as depicted in FIG. 24 , drive ribbon 40B defines an arc withproximal edge section 58B positioned radially inward of distal edgesection 56B. In embodiments where the proximal edge projects radiallyoutward, the proximal edge section will be positioned radially outwardof the distal edge section when the ribbon is positioned in a plane todefine an arc.

Another embodiment 20C similar to device 20B but having a slightlyslimmer profile is shown in FIGS. 30-33 . Device 20C differs from device20B by employing several sheet metal parts that allow for a reduction inthe size of housing support structure. More specifically, a metal baseplate 184, a metal skirt 186 and a metal support bracket 188 areutilized in device 20C.

As most easily seen in FIG. 33 , the motor, gearing, drive ribbon andbobbin are the same as those used in device 20B. Ribbon bearing member100C has a slightly different shape but functions in the same manner asribbon bearing member 100B. As can be seen in FIG. 33 , ribbon bearingmember 100C includes threads 190 for engaging threads 148 of cartridgesleeve 140. Although not shown in the figures for purposes of graphicalclarity, ribbon bearing member 100B includes similar threads forengaging cartridge sleeve 140. Thrust member 88C includes a post 192. Akey 194 on post 192 engages a keyway 196 on baseplate 184 and preventsrelative rotation of post 192 and the support structure of whichbaseplate 184 is a part. Bobbin 104C is rotatably disposed on post 192and a washer 198 encircling post 192 is located between baseplate 184and bobbin 104C to separate bobbin 104C from baseplate 184.

Devices 20 and 20A-20C can be provided with or without what is generallyreferred to as force feedback. Force feedback determines the forceacting on piston 26 and thereby allows the device to know the state ofcontainer 22 and/or position of piston 26.

If the user is relied upon for priming and otherwise confirming thestate of the device, force feedback is not needed. In a device withoutforce feedback, motor speed and current can be monitored to determinethe state of the system and avoid applying excessive torque to ribbon 40and hence excessive force to piston 26. It may be possible that thecurrent-sensing signal-to-noise ratio will be sufficient to detectcontact between distal end of the drive ribbon and piston 26. Generally,the system will initiate and complete each dose with the system open toatmospheric pressure through outlet 28. In such a system, sensing theforce on piston 26, i.e., force feedback, is not necessary for dosingaccuracy.

If a force feedback system is used, the device will know when the distalend of transfer member 84 contacts piston 26. This will allow some usersteps, such as priming, to be fully or partially automated. A simpleforce feedback system could employ a contact switch that triggers at alow force. Such a switch could be located at the distal end 81 of thedrive ribbon and coupled with bearing member 80 or rotational bearing82. Electrical conductors could be disposed on the drive ribbon toprovide electrical communication between the contact switch and aprocessor within the housing. Proportional force sensing is alsopossible by using a force-sensing component such as a force sensitiveresistor instead of a contact switch. The conductors disposed on thedrive ribbon could terminate in or on the storage bobbin. If a rotatingbobbin is used, a continuous connection to the device frame can beprovided by slip rings or other appropriate contacts.

The illustrated embodiments are electro-mechanical and controlled by aprocessor, microcontroller or microcomputer. The use of a processorallows numerous interaction points and additional functions to beincorporated in the device. For example, the user can interact with thedevice using a touchscreen, a multiple-button interface, or specifictouch points (such as a dose-setting wheel). If desired, such controlscould mimic the interaction behaviors of conventional injection devices.

The device could also display a variety of different information such ascurrent dose setting, last dose, reminders and use cues or any otheruseful information. The displays may take the form of a liquid crystaldisplay (LCD), organic light-emitting diode (OLED), electronic paperdisplay (EPD), or other suitable display.

The device can also be provided with connectivity allowing it to connectto and interact with other devices (e.g. smart phones) using eitherwired or wireless communication techniques. These interactions can beused to exchange information in either direction, allowing (forinstance) a health care practitioner to change device settings ordownload dosing history.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles.

What is claimed is:
 1. A drive assembly for a device for use with a container, the container having a container body and a slidable piston therein, comprising: a drive ribbon movable between an axially retracted configuration and an axially extended configuration to advance said piston axially within the container body, the drive ribbon comprising a proximal edge section and a distal edge section, wherein, during movement of the drive ribbon, a retracted portion of the drive ribbon defines a spiral about a drive axis, and an extended portion of the drive ribbon defines a helical column about said drive axis in which the proximal edge section of the drive ribbon is in engaged with the distal edge section that is adjacent to the proximal edge section, wherein the extended portion defines a distal end of the drive ribbon, the distal end of the drive ribbon configured to advance said piston.
 2. The drive assembly of claim 1, wherein the drive ribbon includes a radially inward facing surface and a plurality of gear teeth disposed along the radially inward facing surface.
 3. The drive assembly of claim 1, wherein the drive ribbon includes a radially exterior surface and a plurality of gear teeth disposed along the radially exterior surface.
 4. The drive assembly of claim 1, wherein in the spiral the proximal edge section and the distal edge section lie in a common plane.
 5. The drive assembly of claim 1, wherein the distal edge section of the drive ribbon in the axially retracted configuration lies in a first plane, and the proximal edge section of the drive ribbon in the axially retracted configuration lies in a second plane, wherein the distance between the first and second planes is equivalent to a width of the drive ribbon.
 6. The drive assembly of claim 1, further comprising a thrust member engaged with one of the proximal or distal edge sections, wherein relative rotation between the thrust member and the drive ribbon transitions the retracted portion to the extended portion.
 7. The drive assembly of claim 1, further comprising a bearing member coupled to the distal end of the drive ribbon.
 8. The drive assembly of claim 1, wherein the proximal edge section of the drive ribbon is interlocked with the distal edge section in the extended portion of the drive ribbon.
 9. The drive assembly of claim 1, wherein one of the proximal and distal edge sections defines a radially extending lip to directly engage the other one of the proximal and distal edge sections.
 10. The drive assembly of claim 1, wherein one of the proximal and distal edge sections defines a plurality of projections and the other one of the proximal and distal edge sections defines a plurality of cooperating recesses receiving said projections to form said helical column as an interlocked rigid cylindrical column with axial and torsional strength sufficient to advance the piston.
 11. The drive assembly of claim 1, wherein the drive ribbon is a unitary one-piece ribbon.
 12. The drive assembly of claim 1, further comprising a storage bobbin, the retracted portion of the drive ribbon being stored in the storage bobbin.
 13. The drive assembly of claim 1, further comprising a mechanical drive operably coupled with the drive ribbon to move the drive ribbon between the axially retracted and extended configurations.
 14. The drive assembly of claim 13, wherein the mechanical drive comprises an electrical motor drivably coupled to the mechanical drive.
 15. The drive assembly of claim 1, wherein the proximal edge section defines a proximal edge surface and the distal edge section defines a distal edge surface, the proximal edge surface defining a first axially facing lengthwise portion and a second axially facing lengthwise portion and the distal edge surface defining a third axially facing lengthwise portion and a fourth axially facing lengthwise portion, and, in the extended portion of the drive ribbon defining a helix, the proximal edge section of the ribbon is engaged with an adjacent portion of the distal edge section with the second lengthwise portion of the proximal edge surface engaged with the third lengthwise portion of the distal edge surface and wherein the first lengthwise portion of the proximal edge surface and the fourth lengthwise portion of the distal edge surface extend radially outwardly in opposite directions.
 16. A medical delivery device, comprising: an axially expandable drive assembly; a container having a container body and a slidable piston therein; wherein the axially expandable drive assembly comprises a drive ribbon movable between an axially retracted configuration and an axially extended configuration to advance said piston axially within the container body, the drive ribbon comprising a proximal edge section and a distal edge section, wherein, during movement of the drive ribbon, a retracted portion of the drive ribbon defines a spiral about a drive axis, and an extended portion of the drive ribbon defines a helical column about said drive axis in which the proximal edge section of the drive ribbon is in engaged with the distal edge section that is adjacent to the proximal edge section, wherein the extended portion defines a distal end of the drive ribbon, the distal end of the drive ribbon configured to advance said piston.
 17. The device of claim 16, wherein the container body holds a medicament.
 18. The device of claim 16, wherein at least one of: the distal edge section of the drive ribbon in the axially retracted configuration lies in a first plane, and the proximal edge section of the drive ribbon in the axially retracted configuration lies in a second plane, wherein the distance between the first and second planes is equivalent to a width of the drive ribbon, and the proximal edge section of the drive ribbon is interlocked with the distal edge section in the extended portion of the drive ribbon.
 19. A medical delivery device, comprising: a mechanical drive; an axially expandable drive assembly; a container having a container body and a slidable piston therein; wherein the axially expandable drive assembly comprises a drive ribbon movable between an axially retracted configuration and an axially extended configuration to advance said piston axially within the container body, the drive ribbon comprising a proximal edge section and a distal edge section, wherein, during movement of the drive ribbon, a retracted portion of the drive ribbon defines a spiral about a drive axis, and an extended portion of the drive ribbon defines a helical column about said drive axis in which the proximal edge section of the drive ribbon is interlockable with the distal edge section that is adjacent to the proximal edge section, wherein the extended portion defines a distal end of the drive ribbon, the distal end of the drive ribbon configured to advance said piston, and wherein the mechanical drive is operably coupled with the drive ribbon to move the drive ribbon from the axially retracted configuration to the axially extended configuration.
 20. The device of claim 19, wherein the mechanical drive comprises an electrical motor drivably coupled to the mechanical drive, and the device further comprises a force feedback system operably coupled to the drive ribbon. 